Simple: Jinn is ill-informed. And there are fewer limiting factors on the Jedi-spirit-immortality. Jedi spirits can appear in many places - Yavin, Hoth, and Dagobah for starters are all places where Obi-Wan appeared to guide Luke. AND as far as we know, you cannot destroy Jedi spirits. You very much can destroy Sith spirits - both Freedon Nadd and Exar Kun are good examples.Spartan wrote:Really I guess it depends on what you mean by imortal. After all Exar Kun existed in a concious state for nearly 4,000 years; but he was still eventually killed.
The Sith spirits only survived by binding their spirit to a physical object.
And Palpatine cheats the spirit immortality by inhabiting body after body after body. And in a way, the result does reflect this "cheat" - its is so unnatural that the Force degrades the bodies in just a few years.